The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Network devices, such as network switches, routers, edge devices and the like often need to enqueue data (e.g., received packets or data associated with received packets) in one or more egress queues for subsequent transmission from the network device. When packets are to be transmitted from the network device, the enqueued packets (or enqueued data associated with the packets) need to be de-queued, or read from the memory the holds the corresponding queue before the corresponding packet can be transmitted. Thus, bandwidth that a network device can support is at times limited by the rate of retrieval of packets from a memory in which the data is queued for egress from the network device.
Different levels of service may be provided based upon properties of packets. In some scenarios, a higher level of service is assigned to packets representing interactive traffic than to packets representing bulk file transfers, for example. In other scenarios, the packet processor guarantees a specified bandwidth to some types of traffic and limits the bandwidth available to other types of traffic, for example. Packets corresponding to different levels of service are typically enqueued in respective egress queues that correspond to different levels of service.